SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2e84ffbc6a88dcac311aaa518aab5033a44587b44697ef44e589926b5a24658' 
  AND token = '8+staIRvpPlHyYyTaTDhGyF9ig6FWAggJaqERZiLgko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}